Interstitial cystitis (IC) is a chronic inflammation or irritation of the urinary bladder wall that is estimated to affect between 500,000 and 1,000,000 people in the US (approximately 90% female). The primary symptoms of IC are urinary urgency, frequency, and often-severe pelvic and perineal pain. The similarity of the symptoms of IC with other bladder diseases, such as urinary tract infections (UTI), urethritis, urethral syndrome, trigonitis, prostatitis, dysuria, and nocturia has caused difficulty in the diagnosis of the disease. After other similar bladder diseases are ruled out and a cystoscopic examination of the bladder wall reveals characteristic signs of IC, including small petechial hemorrhages or larger Hunner's Ulcers, IC is usually diagnosed.
The biological cause of IC remains undetermined. The theory that IC is caused by a bacterial infection is controversial. IC patients routinely test negative for infection in standard urinalysis. On the other hand, several studies have shown antibiotic treatment regimens to alleviate symptoms for IC patients. Another possible cause is a defect in the epithelial permeability barrier of the bladder surface glycosaminoglycans (GAG). Once the bladder wall loses the protective coating of GAG, irritative components and potentially pathogenic bacteria in the urine can lead to the inflammation or irritation associated with IC. Another line of research indicates that activated mast cells, which are associated with pain and irritation, are involved in the pathology of IC. Studies have shown that IC patients have an increased level of activated mast cells in the tissues of the bladder wall.
Currently there is no permanent cure for IC in the majority of patients. Treatment of IC with drug therapy has been proven to be the most effective means of alleviating symptoms. Oral medications for IC include bladder-coating agents, antidepressants, antihistamines, antispasmodics, and anesthetics. The effectiveness of oral medications is limited by the circulating concentration of the drug in the blood stream. To address this limitation, many IC patients elect to undergo a procedure called urinary bladder instillation, in which a therapeutic solution is pumped into the bladder through a urethral catheter. The solution, which may be composed of one or a combination of medications, is held in the bladder for a “dwell time” before the bladder is drained or voided. This procedure allows the treatment of the urinary bladder wall directly with high concentrations of medicine. Despite the drawbacks of a limited dwell time for the medication to take effect and the necessary mixture of medication with urine, bladder instillation may be the most effective treatment currently available for IC.